The only time I would take a train would be as a novelty as driving in the long run is always cheaper.
Back in the sixties I used to take a four hour bus ride between RI and the NY Port Authority station, and I hated it. I inquired at the train station and found that it cost as much as flying, so I tried flying. This was actually my first plane flight ever, and it was on a turboprop. Of course, it took longer than the bus when you added everything up, so I went back to the bus. I remember it all very well.
I also remember my Mom telling me about the WWII days when they rode from Philly to South Carolina standing up on the train, which was of course packed. That's all there was then, and this is what it would take to pack the trains - the elimination of all other forms of transportation.